This new liquid flashing from GCP is ideal for difficult detail areas. Perm-a-Barrier is a fluidapplied flashing that protects hard-to-reach areas, such as joints and fasteners, of window and door rough openings from air and water entry. According to GCP, the flashing provides an airtight seal, is water-vapor permeable, and prevents moisture from being trapped in the wall cavity. It fully bonds to framing without priming, adheres to common construction substrates (such as wood, block, concrete, and metal), is damp-surface tolerant, and eliminates the need for joint reinforcement tapes. Pricing varies.